The various organs in the human anatomy are subject to a variety of diseases which can only be diagnosed by cytologic or surgical pathologic examination of cells or tissue recovered by a biopsy procedure. Lung structure particularly presents unique problems with regard to the performance of a biopsy. The lung is enveloped in a thin membrane called the "pleura" which separates the lung from the inside of the chest wall which is similarly covered with a pleural membrane. A minute space called the "pleural space" is provided between the two membranes and if air is allowed to enter the pleural space, the lung will collapse, either partially or completely.
Efforts to biopsy the lung have focused on two requirements:
(1) The need to harvest cells or tissue from an organ which is mostly air, and
(2) The need to obtain a biopsy specimen from within the lung substance without permitting air to leak either from the outside, or from the lung into the pleural space.
Two methods are commonly employed to biopsy the lung: namely, transbronchial wherein a flexible fiberoptic bronchoscope is employed as a conduit through which a biopsy instrument is passed from the outside of the patient through the airways of the lung into the lung tissue: and percutaneous wherein a biopsy needle is introduced through the chest wall usually after making a small skin incision.
While the transbronchial method is satisfactory as to a minimum of complications such as bleeding and lung collapse, the time, one to two hours, and expense in performing this procedure are quite formidable.
The percutaneous method has proven satisfactory as to time and expense; however, the various needles employed, such as the Silverman, Cope and Abrams, while providing relatively large pieces of tissue, produced a sizable injury to the pleural surface of the lung, thus causing a condition which promoted lung collapse. Furthermore, none of the needles was provided with an air seal, resulting in air being introduced from the outside causing the lung to collapse.
Currently, the only satisfactory procedure used for percutaneous lung biopsy is the "Skinny Needle" technique wherein a needle, similar to a standard intravenous needle (18 to 21 gauge) but somewhat longer and having an angled sharp cutting tip, is attached to a syringe. The needle is inserted into the lung through the chest wall and a vacuum is applied to the syringe whereby lung cells are sucked into the needle. The needle is then withdrawn from the chest and the cells forced from the needle onto a microscope slide for examination. This technique is simple since it can be performed frequently at the patient's bedside; it can be performed quickly, 15 to 30 minutes, and inexpensively. Since the needle is of narrow bore and has a sharp cutting tip, the injury to the pleural surface is minimal. This, together with the needle being air-sealed by the syringe, results in lung collapse being far less common than with any other percutaneous technique. The main disadvantage of the "Skinny Needle" technique, making it the least satisfactory of all techniques, is the relative paucity of the cellular material obtained because of the structure of the lung being predominantly air.
To overcome the disadvantage of the currently accepted and widely used "Skinny Needle" method of lung biopsy, and at the same time preserve its advantage in simplicity of use and low instances of complication, the apparatus of the present invention has been devised which comprises, essentially, a cell or tissue retrieving instrument, such as a transbronchial brush biopsy instrument or a Cope needle, slidably mounted within the needle of a conventional "Skinny Needle". The tissue retrieving instrument is connected to the needle syringe piston or plunger, whereby the "Skinny Needle" with the tissue retrieving instrument enclosed therein is inserted inwardly through the chest wall, visceral pleura and into the lung. The tissue retrieving instrument is held fixed and the "Skinny Needle" is moved outwardly to expose the tissue retrieving instrument within the lung. The instrument is then pulled into the "Skinny Needle" and the "Skinny Needle" is removed from the chest wall.
By the construction and arrangement of the apparatus of the present invention, cells are recovered, not by aspiration, but on the cell retrieving instrument, thus providing relatively large pieces of tissue. Since the assembly is air sealed, air leak from outside the chest is impossible, and because the cell retrieving instrument is introduced into the lung through a small cutting needle, pleural damage is no greater than experienced with the "Skinny Needle" technique.
In order to facilitate the manipulation of the "Skinny Needle" and associated cell retrieving instrument which would require a high degree of manual dexterity, and a considerable amount of training and practice, a device has been devised for controlling the sequence of the operation of withdrawing the "Skinny Needle" to expose the tissue retrieving instrument and then pulling the instrument into the needle, after the "Skinny Needle" is inserted into the tissue.
The device comprises, essentially, a housing adapted to receive the "Skinny Needle" and associated cell retrieving instrument. An adjustable gauge is mounted on the end of the housing to limit the depth of insertion of the "Skinny Needle" into the patient. A pair of latched, spring actuated, carriages are slidably mounted within the housing, one carriage being connected to the syringe barrel of the "Skinny Needle" and the other carriage being connected to the syringe plunger of the "Skinny Needle". By this construction and arrangement, the syringe barrel carriage is first released, causing the needle to move relative to the cell retrieving instrument. The syringe barrel then engages the latch of the syringe plunger carriage, to thereby release the plunger carriage, whereby the cell retrieving instrument is pulled into the needle.